Introduction
WAN means a global network. It is many times greater than LAN (local-area network) in its scale. When a network interface is connected to this global network, it is assumed that WAN is accessible from the Internet. WAN can be spread across vast distances and distributed between remote offices located in different parts of the country and the world. This network has fewer nodes than LAN does, but it engages a large number of connected users. The purpose of this paper is to review three WAN protocols and describe data transmission approaches associated with them.
Point-to-Point Protocol
PPP is an abbreviation commonly used for the first type of protocol. This protocol belongs to the second layer of the OSI model (Open Systems Interconnection), which is used on the WAN links. This simple type of protocol has an open character, which makes it possible to use it for connecting devices produced by one manufacturer to devices manufactured by other producers. The point-to-point protocol is rather multifunctional and is used widely (Mutha, 2012). It can function via a special cable or a mobile phone line. Also, this second-level protocol can be encapsulated in other protocols of the same level. If PPP is encapsulated in other protocols, the second protocol will perform the delivery of frames from the sender’s address to the address of the recipient (Mutha, 2012). The receiver will decapsulate the frame from this protocol, and the point-to-point protocol will create an effect of a point-to-point connection. PPP tasks will be to conduct authentication and compress traffic.
The examples of data transmission technologies using the point-to-point protocol can be linked to net access connections. For instance, Internet service providers can use it to ensure dial-up access to the Internet. Also, another example is when service providers need to establish a digital connection for clients. This protocol is used as a link-layer between different types of circuits.
This protocol does not have any limitations related to data transfer speed; however, it requires the provision of duplicated circuits that can work in both synchronous and asynchronous serial mode (Mutha, 2012). Besides, PPP links possess a terabit per second limiting factor. Therefore, its bandwidth limitation can lie in the routing capability of routers.
Packet Switched Protocol
It is a special way of communicating between network nodes. The approach was created to improve the transmission of computer traffic. In this method, messages that are transmitted over the network are split into small parts (packets) (Kim, Ryoo, Lee, Kim, & Lee, 2016). The packet assumes a logically completed piece of data, which can have any length. Each packet receives a header with the address information for the packet delivery and a number for the message assembly (Kim et al., 2016). Switches of this network are characterized by the fact that they have an internal buffer memory for storing packets. This memory is used when the output port is busy transmitting another packet.
Data transmission technologies in this approach can be different. For example, a datagram method may be used in which the transmission is performed as a collection of independent packets. However, this technology is unreliable since packets can be easily lost. A logical channel can also be used, in which sequential transmission of packets is accompanied by the installation of a preliminary connection and acknowledgment of reception. Also, it is possible to transmit messages via a virtual channel. This technology uses a logical channel with the transmission of a message over a fixed route of sequences bound in a chain of packets (Kim et al., 2016). The bandwidth limitations of this technology are related to the pulsating nature of the traffic that generates typical network applications. Even though this technique was designed to improve traffic transmission, it did not provide an opportunity to obtain high throughput.
Circuit Switched Protocol
The circuit-switched protocol assumes an establishment of an uninterrupted composite channel for data transfer between nodes (Sneps-Sneppe, 2015). The important aspect of this approach is that the channel is formed from successively connected individual channel sections. These channels are interconnected using special equipment, which establishes communication between the end nodes of the network (Sneps-Sneppe, 2015). Before sending messages, it is necessary to form a connection and create a compound channel. Switches working on such a protocol should perform data connection and transmission from several channels, which implies such characteristics as high speed and multiplexing support.
An example of the data transfer technology for this protocol is HSCSD technology (High-Speed Circuit-Switched Data) in GSM networks (Global System for Mobile Communications). This technology allows performing mobile access to the Internet, e-mail, fax, and other services. It assumes that connection time and channel establishment time are charged (Sneps-Sneppe, 2015. Another example is a telephone network (line). The connection proceeds through an eternal wire circuit. The bandwidth limitations in this protocol are related to the bandwidth of the channel, the length of the link, and the size of the message (Sneps-Sneppe, 2015). In particular, the bandwidth can be used inefficiently when user equipment operates at different speeds.
Conclusion
Thus, it can be concluded that the interaction between users is carried out using the commutation of communication channels. Because each computer cannot have its non-commutated communication line, each computer network uses a certain way of switching workstations. It makes it possible to link multiple users to enable several communication sessions to occur simultaneously.
References
Kim, D. U., Ryoo, J. D., Lee, J. H., Kim, B. C., & Lee, J. Y. (2016). Protection switching methods for point-to-multipoint connections in packet transport networks. ETRI Journal, 38(1), 18-29.
Mutha, R. (2012). Packet switched networks for communications within large multi-core systems on chip. International Journal of Modeling and Optimization, 2(4), 422-426.
Sneps-Sneppe, M. (2015). Circuit switching versus packet switching. International Journal of Open Information Technologies, 3(4), 27-37.